An unnamed British official told the London Guardian that the prince visited the Kahuta uranium-enrichment plant and missile factory with Pakistani Prime Minister Nawaz Sharif. He was reportedly briefed by A.Q. Khan, the “father of Pakistan’s atom bomb.”

The Kahuta site is said to be so sensitive that Benazir Bhutto, former Pakistani prime minister, was refused permission to visit the facility during her term of office.

India has expressed concern that Pakistan is developing an “Islamic bomb,” a term referring to the possibility that Pakistan could share its nuclear technology with other Muslim nations.

Diplomatic sources in London were quoted as saying there was concern that Saudi Arabia might have agreed to finance the Pakistani effort and might try to buy missiles and nuclear know-how.

“Proliferation has got to be pushed up the agenda in the interests of everyone,” the official said. “What is happening is very serious.”